Automatic control for sprinkler systems



March 14, 1967 R. M. ALsToN ETAL v AUTOMATIC CONTROL FOR vSPRINKLERSYSTEMS Filed July 22, 1963 2 Sheets-Sheet 1 March 14, 1967 R. M. ALSTONETAL 3,309,543

AUTOMATIC CONTROL FOR SPRINKLER SYSTEMS Filed July 22, 1963 2Sheets-Sheet 2 gz/Z622.

` INVENTOR5.

United States Patent 3,309,543 AUTOMATIC CONTROL FOR SPRINKLER SYSTEMSRussell M. Alston, West Covina, and Carl R. Sharp, Glendora, Calif.,assignors to Rain Bird Sprinkler Mfg. Corp., Glendora, Calif., acorporation of California Filed July 22, 1963, Ser. No. 296,844 12Claims. (Cl. 307-141.4)

This invention relates to a system for controlling sprinkler operationand more particularly relates to such a system for controlling the day,hour and timing interval of operation of each of a plurality ofsprinkler stations.

It is an object of the present invention to provide an electrical systemfor establishing the days and hours at which a plurality of sprinklingstations operate and the sprinkling interval of each sprinkling station.

It is also an object of the present invention to provide such a systemin which easily set, serially connected switches determine the day andhour at which the entire sprinkling system is to operate and individualpotentiometers determine the timing interval for each individualsprinkling station.

It is another object of the present invention to provide such a systemin which the timing interval of each station is not affected byuctuations in line voltage.

It is a further object o=f the present invention to provide such asystem in which a transistor amplifier is used to sense the end of thetiming interval of a station and initiate the operation of furtherapparatus which terminates the sprinkling action of that station andbegins the sprinkling action of the next succeeding station.

These and other objects of the present invention will become moreapparent upon reference to the accompanying description and drawings inwhich:

FIGURE 1 is a schematic diagram of the electrical control circuit of thepresent invention; and

FIGURE 2 is a schematic diagram of a modification of the control circuitof the present invention.

Briefly, this invention provides a system in which a pair ot' switchbanks corresponding to hours of the day and days of the week areconnected in series with a power supply to produce an output when aclock indicates that a selected hour and day have arrived. A bridgecircuit made up of a master potentiometer and an adjustablepotentiometer corresponding to one of the sprinkling stations producesan output signal indicative of the ydierent settings of the respectivepotentiometer Wiper arms, the wiper arm of the master potentiometerinitially being in a zero voltage drop position. The output from theswitching circuit energizes a motor which drives the masterpotentiometer arm until the bridge is balanced. A transistor amplifiersenses this balance and energizes a motor which disconnects the firstadjustable potentiometer from an eiiective position and connects anotherpotentiometer corresponding to the next sprinkler station into thebridge circuit. The cycle is then repeated for each of a plurality ofpotentiometers corresponding to each of the sprinkler stations beingcontrolled.

Referring now to the drawing, a power supply has its input connected tostandard 115 volt, 60 cycle power lines 11 and has a pair of outputs 12and 13 for providing reduced voltages, for example 24 volts, to thecontrol system. One side of 4output 12 is grounded and the other side isconnected through a switch 14 and conductors 15 and 16 to the contactarm 17 of a switch 18, one stationary Contact 19 of which is floating.The other stationary contact 20 of the switch 18 is connected by aconductor 24 to the wiper arm 25 of a rotary switch 26. The rotaryswitch 26 has twenty-four contacts 27, each contact corresponding to onehour of the day. n

Each of the contacts 27 of the rotary switch 26 is convice nected to oneof the contact arms 29 of a switch bank 30. All of the stationarycontacts 31 of the switch bank 30 are connected to all of the contacts33 of a second switch bank 34 by a common conductor 32.

The switch bank 34 has 14 individual switches, each of the switchescorresponding to one of the days in a twoweek period. The movablecontact arm 4t) of each alternate switch of the switch bank 34 isconnected to one of the contacts 41 of a rotary switch 42. The wiper arm43 of the rotary switch 42 is connected to one of the xed contacts 44 ofa switch 45 having a contact arm 46 and a second xed contact 47connected to the wiper arm 48 of a second rotary switch 49. Each of thecontacts 50 of the rotary switch 49 is connected to one of the remainingcontact arms 40- of the switch bank 34.

A clock motor 54 having an exciting winding 55 is driven at the rate ofone revolution per hour. The output shaft of this motor is connectedthrough gears 56 to a disk 57 that has a pair of cutouts 58 formed inthe outer periphery thereof. The disk 57 cooperates with the contact arm17 of the switch 18 and is driven at the rate of twelve revolutions perday so that once every hour the contact arm 17 is able to engage thecontact 20 of the switch 18 yfor a period of time determined by the sizeof the cutouts 58.

The wiper arm 25 of the rotary switch 26 is also driven by the clockmotor 54 through gears 59, the gearing ratio of the gears 59 'being suchthat the wiper arm 25 is driven at the rate of one revolution per day.The output olf gears 59 is also mechanically coupled through lfurthergears 60 to a disk 61 which has a cutout surface 62 over half itsperiphery, and thence through gears 63 to the wiper arms 48 and 43 ofthe rotary switches 49 and 42. The gearing ratio of gears 60 and 63 issuch that the disk 61 is driven at the rate of onehalf revolution perday while the wiper arms 48 and 43 of the rotary switches 49 and 42 aredriven at the rate of one revolution per two weeks.

The circuitry just described enables a pulse to be produced at any hourof any day over a two week period. The even number of days in the cyclepermits the various sprinkling stations to be actuated on an alternateday basis if desired. As can be seen, the switch banks 30 and 34 areused to determine when the pulse is to be produced. If, for example, itis desired to actuate the sprinkler stations on the fourth hour of everyalternate day, the contact arm 29 of the switch bank 30 corresponding tothe 4fourth hour is manually closed as are the contact arms 40 of theswitch bank 34 corresponding to Sunday, Tuesday, Thursday, Saturday,lvlonday, and so forth.

Assuming that it is Sunday of the rst week, there will be an opencircuit until the motor 54 drives the wiper arm 25 of the rotary switch26 around to the contact corresponding to the fourth hour. As the wiper25 engages this contact, the disk 57 will be in a position such that thecontact arm 17 of the switch 18 moves into the cutout 58 thus permittingthe contact arm 17 to engage the contact 20. A circuit is now completedthrough switch 14, conductor 15, conductor 16, contact arm 17, contact20, conductor 24, wiper arm 25, switch 30, conductor 32, switch 34,contact 41, wiper arm 43 of rotary switch 42, contact 44 of switch 45and contact arm 46 of the switch 45, resulting in an output pulseappearing on a conductor 66 connected to the contact arm 46.

The disk 61 has a configuration such that the Contact arm 46 is kept inengagement with the contact 44 on` every other day and in engagementwith the contact 47 on the alternate days. The rotary switches 42 vand49 thus are connected into the circuit on alternate days of the two weekperiod, the days on which their contacts 41 and 3 50 respectively areconnected to the various switches of the switch bank 34.

Shortly after the output pulse is produced, the circuit is broken as thecontinued rotation of the disk 57 causes the contact arm 17 to ride upout of the coutout 53 and disengage the contact 29.

The output pulse produced by this switching circuit is fed by theconductor 66 to the exciting winding 67 of the master potentiometerdrive motor 63. The motor 63 drives the wiper arm 69 of a masterpotentiometer 7) through gears 71. The potentiometer 7@ is connectedacross the output 13 of the power supply 10, a rec-tier 72 and a lteringcapacitor 73 being provided to rectify the output voltage. The wiper arm69 is connected to ground through a variable resistor 74. The wiper arm69 is also connected to the conductor 66 by means of a resistor 77, arectier 79, and a filtering capacitor 89. The resistors 77 and 74 thusact as a voltage divider to establish a potential on the wiper arm 69which depends on the adjustment of the resistor 74.

A plurality of potentiometers 81A-81K are connected across the rectifiedand ltered output of the power supply 13 in parallel with thepotentiometer 7i). Each of the wiper arms 82A-82K of the potentiometers81A-81K are connected to one of the contacts 83 of a rotary switch 84.These eleven potentiometers and their respective contacts correspond tothe eleven sprinkler stations controlled by the present system. Anynumber of such sta tions can, of course, be controlled by varying thenumber of potentiometers and contacts. .The wiper arm 85 of the rotaryswitch 84 is connected by a resistor 86 to the input of an amplifierindicated generally at 87.

As can be seen, the master potentiometer 70 and the potentiometers{51A-81K form a plurality of bridge circuits, each of which has anoutput appearing between the wiper arm 69 and one of the Wiper arms82A-82K. These outputs are sequentially sampled by means of the wiperarm 85 of the rotary switch 84. By setting the wiper arms of thepotentiome-ters SIA-81K at various points, the sprinkler stations can becaused to be actuated for any desired time interval up to the maximumprovided for by the `master potentiometer. When the wiper arm of theselected potentiometer is, yfor example, set at its half way mark, thelbridge will produce an output voltage which is the diierence betweenthe voltage on the wiper arm 69 which is initially positioned on thehigh voltage side of the potentiometer 70 and the voltage on the wiperarm of the selected potentiometer.

As the wiper arm 69 is driven across the potentiometer 70 by the motor68, this diierence voltage will decrease until the bridge is balanced,at which time the voltage appearing between the wiper arm of theselected potentiometer `and the arm 69 will be equal Ito that appearingacross resistor 74. It can thus be seen that by having the motor 68 takean hour to drive the arm 69 across the potentiometer 70, the time duringwhich 4the bridge is unbalanced can be established at any interval up toan hour. In order that the bridge be balanced when the sprinkling cycleis initiated, the rotary switch 85 is provided with an extra contact 88which is connected by a conductor 89 to the positive lead.

The amplifier 87 is conventional and comprises a pair 'of cascaded NPNltransistors 94 and 95, the transistor 94 being connected as an emitterfollower and having its base connected to the wiper arm 85 of the rotaryswitch 84 .through the Iresistor 86. The output of the transistor 94 isconnected to the input of the transistor 95, which transistor isconnected to the conductor 66 through Ithe rectier 79 and the winding 96of a relay 97. The colvlector of the transistor 94 is also connected tothe conductor 66 lthrough the rectifier 79 and a resistor 98. A resistor99 and a diode 100 serve to prevent any substantial reverse current fromflowing through the transistor 94, a condition which exists until thearm 69 of the potentiometer 70 is driven to the balance point causingthe reversal of the polarity of the output from the bridge circuit.Transistor 94 is biased by the potential appearing across resistor 74.

The transistor 94 is biased such that it will be in a nonconductivestate when the bridge is unbalanced but will be switched to theconductive state when the bridge becomes balanced. Thus, when the arm 69of the potentiometer 70 is driven to a position such that it balancesthe bridge, the transistor 94 will begin to conduct, causing thetransistor 95 to conduct and a c-urrent to flow through the winding 96of the relay 97.

Current flow through the winding 96 of the relay 97 will cause thearmature 193 of the relay 97 to be drawn down into engagement with thecontact 164, thus cornpleting a circuit from the conductor 66, throughthe conductor 105, armature 103, contact 104, conductor 106, conductor107 and conductor 103 to the exciting winding `109 of a motor 110. Themotor 110 drives a first disk 111,- a second disk 112, the wiper arm 85of the rotary switch 84, and the wiper arm 113 of a rotary switch 114.The disk 111 has twelve notches 115 formed therein, each of the notchescorresponding to one of the contacts 83 of the rotary switch 84. Thedisk 112 has a pip 116 formed thereon which is in the position shownwhen the wiper arm 85 of the rotary switch 84 engages the contact 88thereof.

The disk 111 cooperates with the movable arm 117 of a switch 118 whichhas a rst floating contact 119 and a second Contact 120 connected by aconductor 121 and a conductor 112 to the switch 14. The movable arm 117of the switch 118 is connected to the junction between the conductors107 and 16S.

The disk 112 cooperates with the movable arm 125 of a switch 126 whichhas a first oating Contact 127 and a second contact 12S which isconnected by a conductor 129 to the armature 103 of the relay 97.

A switch 131) has its moving arm 131 mechanically linked to the movablearm 117 of the switch 118. The switch has a first oating contact 132 anda second contact 133 which is connected by a conductor 134 to the wiperarm 113 of the rotary switch 114. The rotary switch 114 has a firstloating Contact 135 and eleven other contacts 136, each of which isconnected to a valve actuating device such as a solenoid which controlsone of the sprinkler stations A-K. The contact 128 of the` switch 126 isalso connected by a conductor 137 to the valve actuator of the sprinklersystem master valve. The other terminal of the solenoidsv or other valveactuating devices is grounded so as to complete the circuit.

A limit switch 133 is mechanically coupled to the arm 69 of thepotentiometer 76 to form a short circuit be tween the conductor 129 andthe conductor 197 in the eventuality that the arm 69 should for somereason be driven past the sixty minute position on the potentiorrv eter'70.

In explaining the operation of the complete system, let it rst beassumed that the clock motor 54 has driven the wiper arm 25 of therotary switch 26 until it engages a Contact 27 whose hour switch 29 andday switch 34 are closed so that a voltage appears on the conductor 66and across the winding 67. Energization of the winding 67 results in themotor 68 beginning to rotate so as to drive the wiper arm 69 of thepotentiometer 70. At this time, however, the voltage appearing on thewiper arm 85 of the rotary switch 84 is the balance voltage, that is,the voltage appearing at the junction between the resistor 77 and 74 asa result of the voltage appearing on the line 66. Since the transistor94 is biased to conduct when this balance voltage is applied to itsbase, it immediately begins to conduct, causing conduction in thetransistor 94 and a tlow of current from the conductor 66 through therectifier 79 and coil 96 of relay 97.

Energization of the winding 96 of the relay 97 causes the armature 193to be drawn down into engagement with the contact 104, thus completing acircuit from theconductor 66 through the conductor 105, armature 103,contact 104, conductor 106, conductor 107 and conductor 108 to theexciting winding 109 of the motor 110. The motor 110 now begins torotate in the clockwise direction, driving the disk 111, disk 112, Wiperarm 85 and wiper arm 113. As the disk 111 rotates, the end of the movingarm 117 of the switch 118 is driven up out of a notch 115 and engagesthe Contact 120, thus completing a holding circuit to the winding 109from the out* put 12, through the switch 14, the conductor 122, theconductor 121, contact 120, arm 117 and conductor 108. This holdingcircuit is necessary because the instant that the wiper arm 85 leavesthe contact 88, the balance voltage is removed from the base of thetransistor 94 and this transistor and the transistor 95 go unconductivewith the result that the relay winding 96 is de-energized and the relaycontacts are opened, thus breaking the starting circuit of the motor110.

As the disk 112 is rotated, the pip 116 moves away from under the arm125 of the switch 126 with the result that this `arm moves down andengages the contact 128, completing a circuit to the armature 103 of therelay 97 from the output 12, through the switch 14, the conductor 122,arm 125, contact 128 and conductor 129. This circuit is now used tosupply the starting current to the motor 110 for the remainder of thesprinkling cycle. Immediately after this circuit is completed, the clockmotor 54 has driven the disk 57 suiciently to cause the end of the arm17 of the switch 18 to move up out of the cutout 58 thus breaking thecircuit through the hour and day switching system. The sprinkler controlsystem is now completely independent of this switching system andremains so until all the sprinkling stations have been sequentiallyactuated.

This provision is made because the combined sprinkling intervals set onthe potentiometers {51A-81K may be longer than the time during which thewiper arm 25 of the rotary switch 26 moves from one contact 27 having aclosed switch 29 associated therewith to the next succeeding Contact 27having a closed switch 29 associated therewith. This system also permitsthe combined sprinkling time to be considerably less than one hour, asituation which is highly desirable for newly planted grass. The timingcooperation between the disks 57 and 112 is of course determined by thesize of the cutouts S and the pip 116.

When the motor 110 has driven the disk 111 onetwelfth of a revolution,the end of the arm 117 again' drops into one of the notches 115,breaking the circuit to the winding 109 and de-energizing the motor 110.At this time, the wiper arm 85 of the rotary switch 84 has engaged itsfirst contact 83 and the wiper arm 113 of the rotary switch 114 hasengaged its corresponding contact 136. Since the arm 117 is in its lowerposition, the arm 131 of the switch 130 is also in its lower positionand is in engagement with the contact 133. As arm 131 is connected by aconductor 139 to the output 12 of the power supply 10, a circuit iscompleted through the conductor 139, arm 131, contact 133, conductor134, wiper arm 113 and contact 136 to the valve actuating device ofsprinkler station A. In the meantime, the master valve has been actuatedthrough the switch 126 and conductor 137 so that the sprinklers makingup sprinkler station A begin to sprinkle.

As soon as the wiper arm 85 of rotary switch 84 has engaged the rstcontact 83, the potentiometer 81A has been connected into the bridgecircuit with the master potentiometer 70. Unless the potentiometer wiperarm 82A has been set at zero time, an unbalance exists and an unbalancevoltage is fed to the base of the transistor 94 with the result thatthis transistor remains in its nonconducting state. The masterpotentiometer motor 68 now begins to drive the wiper 69 of thepotentiometer 70, the circuit to the winding 67 of the motor beingcompleted through the arm 125 and contact 128 of the 5 switch 126, theconductor 129 and the conductor 105'.

As the arm 69 moves across the potentiometer 70, it eventually reachesthe balance position and the voltage on the wiper arm again becomes thebalance voltage determined by the voltage divider 77-74. This voltagecauses the transistors 94 and 95 to conduct, the relay coil 96 to beenergized and the motor 110 again begins to rotate. As the wiper arm 85leaves the contact 83, the balance voltage is removed from the base ofthe transistor 94 so the relay winding' 96 is de-energized. The arm 117has in the meantime been driven up out of the notch and into engagementwith the contact so that the motor 112 continues to rotate to the nextposition. Movement of the arm 117 causes corresponding movement of thearm 131 with the result that the circuit to the valve actuator ofsprinkler station A is broken and the valve closes causing sprinkling atthis station to cease. Simultaneously, the wiper arm 69 of thepotentiometer 70 is returned to the zero position in the manner setforth in our copending application filed concurrently herewith andentitled, Cycling Mechanism for Sprinkler System Controllers.

This cycle continues, each potentiometer 81B through 81K kbeingconnected in turn into the bridge circuit, thus actuating its respectivesprinkler station for the time interval set by the potentiometer wiperarms 82B- 82K. After the last sprinkling station has been actuated, themotor 110 drives the disks 111 and 112 and the Wiper arms 85 and 113back to their initial position. At this time, the pip 116 in the disk112 has moved the arm away from the contact 128 thus breaking the mainenergizing circuit. The wiper arm 85 has been driven back intoengagement with the contact S8 so the Voltage appearing on the wiper arm85 is the balance voltage and the transistors 94 and 95 are again readyto conduct when a voltage appears on the line 66. The wiper arm 113 isin engagement with the iioating contact 135 of the rotary switch 114 sothat none of the valve actuators are energized. The circuit to themaster valve is also broken at the switch 116 so that this valve is alsoclosed.

In the event that it is desired to skip one or more of the sprinklingstations without altering their respective potentiometers, the switch isprovided. Closure of the switch 140 completes a circuit from the output12 of the power supply 10 through the switch 14, conductor 15, and aconductor 141 to the conductor 107 and then to the winding 109 of themotor'110. Closure of this switch 140 thus enables the motor 110 to bedriven until the desired sprinkler station is reached.

FIGURE 2 illustrates a modication of the control circuitry which permitstwice as many sprinkler stations to be controlled without increasing thenumber of potentiometers employed.- In this figure, the same referencenumerals are used to identify the same elements that appeared inFIGURE 1. In this modication, the contact 133 of the switch 130 isconnected by a conductor 142 to the movable arm 143 of a switch 144. Afirst contact 145 of this switch is connected to the wiper arm 113 ofthe rotary switch 114. A second contact 146 of a switch 144 is connectedt-o the wiper arm 147 of a rotary switch 148. yThe rotary switch 148 issimilar to the rotary switch 114 and has eleven contacts 149, each ofwhich is connected to a valve actuating device which controls one of thesprinkler stations L-V.

The rotary switch 148 has an additional contact 150 that is connected bya conductor 151 to the exciting winding 109 of the motor 110. A disk 152having a cutout surface 153 over half its periphery is driven by themotor 110 through gears 154 at one half the speed of the motor 110. Alamp 155 is connected to the contact 146 of the switch 144 to indicatethat the sprinkler stations L-V are being operated.

When the disk 152 is in the position shown, the wiper arm 113 of therotary switch 114 is connected to the contact 133 of the switch 130 andthe system operates exactly as explained in connection with FIGURE l.After the operating cycle of stations A-K is completed, the disks 111and 112 and wiper arms 85 and 113 have reached the initial position asshown in FlGURE l. In this position, however, the disk 152 has rotatedto a position such that the movable arm 143 of the switch 144 issupported by the greater diameter portion of the disk 152 andconsequently engages the contact 146 of the switch 144.

This contact is connected to the wiper arm 147 of the rotary switch 148,the wiper arm 147 being inrengagement with the contact 150. A circuit isthus completed through the conductor 139, switch 139, conductor 142,switch 144, rotary switch 148, and conductor 157 to the exciting winding109 of the motor 110. The motor 110 is therefore caused to drive to therest position and the cycle is again completed, the potentiometers 81A-81K this time acting to control the sprinkling intervals of thesprinkler stations L-V. At the end of this cycle, the movable arm 143 ofthe switch 144 rides back down to the cutout portion 153 of the disk 152with the result that all circuits to the winding 109 of motor 11th arebroken and the system remains passive until the next signal appears onthe conductor 66.

From the foregoing description, it can be seen that a `contr-ol systemhas been provided for automatically actuating a plurality of sprinklerstations at any hour on any day. The system permits any desired wateringcycle by providing a two-week rather than a oneeweek switching system.The watering interval of each sprinkling station can be easily adjustedwithout in any way bearing any of the other parts of the circuit. Atransistor amplifier is used as the output device of a doublepotentiometer bridge circuit to insure rapid and dependable response tobridge balance. The use of the bridge as a timing circuit eliminates thepossibility of uctuations in line voltage affecting the timing intervalof the sprinkler stations. By use of the modification of FIGURE 2, thenumber of Stations controlled can be doubled with no increase in thenumber of potentiometers utilized.

The invention may be embodied in other speciiic forms not departing fromthe spirit or central characteristics thereof. The present embodimentsare therefore to be considered in all respects as illustrative and notrestrictive, the scope of the invention being indicated by the appendedclaims rather than by the foregoing description, and all changes whichcome within the meaning and range of equivalency of the claims aretherefore intended to be embraced therein.

We claim:

1. A system for controlling a plurality of sprinkler stationscomprising:

a power supply;

a motor;

means connecting said power supply with said motor to energize saidmotor, said connecting means including first switch means for permittingcurrent dow through said connecting means at selected hours of the dayand second switch means for permitting current ow through saidconnecting means on selected days of the week;

a master potentiometer connected to said power supply;

means drivingly connecting the wiper arm of said master potentiometer tosaid motor;

a plurality of adjustable potentiometers, each of said potentiometerscorresponding to one of said sprinkler stations, said adjustablepotentiometers being connected to said power supply to form a pluralityof bridge circuits with said master potentiometer, the output of eachbridge circuit appearing between the wiper arm of the masterpotentiometer and the wiper arm of the respective adjustablepotentiometer;

a switch having a plurality of contacts and means for sequentiallyengaging said contacts, each of said contacts being connected to thewiper arm of one of said adjustable potentiometers;

a transistor ampliiier having an input and an output,

said input being connected to said sequentially engaging means of saidswitch; f

a relay having a coil and a pair of contacts engageable by energizationof said coil, said coil being connected in series with said output ofsaid amplifier whereby it is energized upon conduction of saidamplilier;

a second motor;

means drivingly connecting said second motor with said sequentiallyengaging means of said switch; and

means for connecting said motor to said power supply,

said means including said contacts of said relay.

2. A system for controlling a plurality of sprinkler stationscomprising:

a power supply;

a motor;

means connecting said power supply with said motor to energize saidmotor, said connecting means including irst switch means for permittingcurrent flow through said connecting means at selected hours of the dayand second switch means for permitting current ow through saidconnecting means on selected days of the week;

a master potentiometer connected to said power supply;

means drivingly connecting the wiper arm of said master potentiometer tosaid motor;

a plurality of adjustable potentiometers, each of said potentiometerscorresponding to one of said sprinkler stations, said adjustablepotentiometers being connected to said power supply to form a pluralityof bridge circuits with said master potentiometer, the output of eachbridge circuit appearing between the wiper arm of the masterpotentiometer and the wiper arm of the respective adjustablepotentiometer;

a voltage divider having one end connected to said means connecting saidpower supply with said motor and the other end grounded;

means connecting the wiper arm of said master potentiometer to anintermediate point of said voltage divider;

a switch having a plurality of contacts and means for sequentiallyengaging said contacts, each of said con tacts being connected to thewiper arm of one of said adjustable potentiometers;

a transistor amplifier having an emitter-collector circuit connectedbetween said means connecting said power supply with said motor andground;

means for connecting the base of said transistor to said sequentiallyengaging means of said switch;

a relay having a coil and a pair of contacts engageable by energizationof said coil, said coil being connected in series with saidemittencollector circuit;

a second motor;

means drivingly connecting said second motor with said sequentiallyengaging means of said switch; and

means for connecting said motor to said power supply,

said means including said contacts of said relay.

3. A system for controlling a plurality of sprinkler stationscomprising:

a power supply;

a irst switch having a plurality of contacts and means for sequentiallyengaging said contacts;

means for connecting said sequentially engaging means to said powersupply;

a iirst plurality of switches each having a pair of relatively movablecontacts, a iirst contact of each of said switches being connected toone of said contacts of said first switch;

a second plurality of switches each having a pair of relatively movablecontacts;

`means connecting each of said second contacts of said first pluralityof switches with each of the first contacts of said second plurality ofswitches;

a second switch having a plurality of contacts and means forsequentially engaging said contacts;

the second contact of each of said second plurality of switches beingconnected to one of the contacts of said second switch;

a motor including an exciting winding;

means connecting said exciting winding to said sequentially engagingmeans of said second switch;

a master potentiometer connected to said power supply;

means drivingly connecting the wiper arm of said mas` ter potentiometerto said motor;

a plurality of adjustable potentiometers, each of said potentiometerscorresponding to one of said sprinkler stations, said adjustablepotentiometers being connected to said power supply to form a pluralityof bridge circuits with said master potentiometer, the output of each ofsaid bridge circuits appearing between the wiper arm of the masterpotentiometer and the wiper arm of the respective adjustablepotentiometer;

a third switch having a plurality of contacts and means for sequentiallyengaging said contacts, each of said contacts being connected to thewiper arm of one of said adjustable potentiometers;

a transistor amplifier having an input and an output,

said input being connected to said sequentially engaging means of saidthird switch;

a relay having a coil and a pair of contacts engageable by energizationof said coil, said coil being connected to said output of said amplifierwhereby it is energized upon conduction by said amplifier;

a second motor including an exciting winding;

means electrically connecting said exciting winding with one of saidcontacts of said relay;

means connecting said other contact of said relay to said sequentiallyengaging means of said second switch; and

means drivingly connecting said sequentially engaging means of saidthird switch to said second motor.

4. A system for controlling a plurality of sprinkler stationscomprising:

a power supply; a first switch having a plurality of contacts and meansfor sequentially engaging said contacts;

means for connecting said sequentially engaging' means.

to said power supply; v

a first plurality of switches each having a pair of relatively`movablecontacts, a first Contact of each of said switches being connected toone of said contacts of said first switch;

a second plurality of switches each having a pair of relatively movablecontacts;

means connectingeach of said second contacts of said first plurality ofswitches with each of the first contacts of said second plurality ofswitches;

a second switch having a plurality of contacts and means forsequentially engaging said contacts;

the second contact of each of said second plurality of switches beingconnected to one of the contacts of said second switch;

a motor including an exciting winding;

means connecting said exciting winding to said sequen tially engagingmeans of said second switch; a master potentiometer connected to saidpower supply; means drivingly connecting the wiper arm of said masterpotentiometer to said motor; a voltage divider having one end connectedto said means connecting said exciting winding to said sequentiallyengaging means of said second switch;

means connecting the wiper arm of said master potentiometer to anintermediate point on said voltage divider;

a plurality of adjustable potentiometers, each of said potentiometerscorresponding to one of said sprinkler stations, said adjustablepotentiometers being connected to said power supply to form a pluralityof bridge circuits with said master potentiometer, the output of each ofsaid bridge circuits appearing between the wiper arm of the masterpotentiometer and the Wiper arm of the respective adjustablepotentiometer;

a transistor amplifier having an input and an output;

means for sequentially coupling said amplifier input with the output ofeach of said bridge circuits; and

means coupled to said amplifier and responsive to an output signaltherefrom for actuating said sequentially coupling means.

5. A system for controlling a plurality of sprinkler stationscomprising:

a power supply;

a first switch having a plurality of contacts and means for sequentiallyengaging said contacts;

means for connecting said sequentially engaging means to said powersupply;

a first plurality of switches each having a pair of relatively movablecontacts, ai first contact of each of said switches being connected toone of said contacts of said first switch;

a second plurality of switches each having a pair of relatively movablecontacts;

means connecting each of said second contacts of said first plurality ofswitches with each of the first contacts of said second plurality ofswitches;

a second switch having a plurality of contacts and means forsequentially engaging said contacts;

the second contact of each of said second plurality of switches beingconnected to one of the contacts of said second switch; Y

a motor including an exciting winding;

means connecting said exciting winding to said sequentially engagingmeans of said second switch;

a master potentiometer connected to said power supply;

means drivingly connecting the wiper arm of said master potentiometer tosaid motor;

a voltage divider having one end connected to said means connecting saidexciting winding to said sequentially engaging means of ysaid secondswitch and therother end grounded; y

means connecting the wiper arm of said master potentiometer to anintermediate point on said voltage divider;

a transistor amplifier having an input and an output;

a Vplurality yof adjustable potentiometers, each of said potentiometerscorrespon-ding to one of said sprinkler stations, said adjustablepotentiometers being connected to said power supply to form a pluralityof bridge circuits with said master potentiometer;

means for sequentially coupling said amplifier input between the wiperarm of each of said adjustable potentiometers and ground, said amplifierbeing biased to conduct when a bridge balance signal appears at theinput thereof; and

means coupled to said amplifier and responsive to conduction thereof foractuating said sequentially coupling means.

6. A system for -controlling a plurality of sprinkler stationscomprising:

a power supply;

a first switch having a plurality of contacts and means for sequentiallyengaging said contacts;

means for connecting said sequentially engaging means to said powersupply;

a first plurality of switches each having a pair of relatively movablecontacts, a first Contact of each of said switches being connected toone of said contacts of said first switch;

a second plurality of switches each having a pair of relatively movablecontacts;

means connecting each of said second -contacts of said first pluralityof switches with each of the first contacts of said second plurality ofswitches;

a second plurality of switches each having a pair of contacts and an armfor electrically connecting said contacts, the first contacts of saidswitches being electrically connected in series with the second contactsof said first plurality of switches;

a third switch having a plurality of contacts and means for sequentiallyengaging said contacts;

the second contact of each of said second plurality of switches beingconnected to one of the contacts of said third switch;

a motor including an exciting winding;

means connecting said exciting winding to said sequentially engagingmeans of said second switch;

a master potentiometer connected to said power supply;

means drivingly connecting the wiper arm of said master potentiometer tosaid motor;

a plurality of adjustable potentiometers, each of said potentiometerscorresponding to one of said sprinkler stations, said adjustablepotentiometers being connected to said power supply to form a pluralityof bridge circuits with said master potentiometer, the output of each ofsaid bridge circuits appearing between the wiper arm of the masterpotentiometer and the wiper arm of the respective adjustablepotentiometer;

a second motor including an exciting winding;

means for energizing said exciting winding of said second motor upon thebalancing of one of said bridges;

a fourth switch having a plurality of contacts and means forsequentially engaging said contacts, each of said contacts beingconnected to the wiper arm of one of said adjustable potentiometers,said sequentially engaging means being coupled to said energizing means;

a fth switch having a pair of relatively movable contacts;

means electrically connecting said' exciting winding of said secondmotor to one of said contacts of said fifth switch;

means electrically connecting the other contact of said fifth switch tosaid power supply;

means for periodically engaging said contacts of said fifth switchwhereby a circuit is completed to the exciting winding of said secondmotor;

means drivingly connecting said sequentially engaging means of saidfourth switch and said means for periodically engaging said contacts ofsaid fifth switch with said second motor, said connecting means causingsaid periodically engaging means to engage said contacts of said fifthswitch while said sequentially engaging means of said fourth switch isunengaged with any of the contacts thereof; and

a holding circuit for connecting said power supply with said excitingwinding of said first motor during the time that said contacts of saidfourth switch are being sequentially engaged.

7. A system for controlling a plurality of sprinkler stationscomprising:

a second plurality of switches each having a pair of relatively movablecontacts;

means connecting each of said second contacts of said first plurality ofswitches with each of the first contacts of said second plurality ofswitches;

a second switch having a plurality of contacts and means forsequentially engaging said contacts;

the second contact of each of said second plurality of switches beingconnected to one of the contacts of said second switch;

a motor including an exciting winding;

means connecting said exciting winding to said sequentially engagingmeans of said second switch;

a master potentiometer connected to said power supply;

means drivingly connecting the wiper arm of said master potentiometer tosaid motor;

a plurality of adjustable potentiometers, each of said potentiometerscorresponding to one of said sprinkler stations, said adjustablepotentiometers being connected to said power supply to form a pluralityof bridge circuits with said master potentiometer, the output of each ofsaid bridge circuits appearing between the wiper arm of the masterpotentiometer and the wiper arm of the respective adjustablepotentiometer;

a third switch having a plurality of contacts and means for sequentiallyengaging said contacts, each of said contacts being connected to thewiper arm of one of said adjustable potentiometers;

a transistor amplifier having an input and an output,

said input being connected to said sequentially engaging means of saidthird switch;

a relay having a coil and a pair of contacts engageable by energizationof said coil, said coil being connected in series with said output ofsaid amplifier whereby it is energized upon conduction by saidamplifier;

a second motor including an exciting winding;

means electrically connecting said exciting winding with one of saidcontacts of said relay;

means connecting said other contact of said relay to said sequentiallyengaging means of said second switch;

a fourth switch having a pair of relatively movable contacts;

means electrically connecting said exciting winding of said second motorto one of said contacts of said fourth switch;

means electrically connecting the other contact of said fourth switch tosaid power supply;

a fifth switch having a pair of relatively movable contacts;

means connecting one of said contacts of said fifth switch to said powersupply;

means connecting the other contact of said fifth switch to said othercontact of said relay;

means for periodically engaging said contacts of said fourth switch;

means for periodic-ally disengaging said contacts of said fifth switch;

-a sixth switch having a plurality of contacts and means forsequentially engaging said contacts;

a seventh switch having a pair of relatively movable contacts;

means electrically connecting one of said contacts with said powersupply;

means electrically connecting the other of said contacts of said seventhswitch with said sequentially engaging means of said sixth switch;

means for periodically engaging said contacts of said seventh switch;

means drivingly connecting said sequentially engaging means of saidsixth switch, said sequentially engaging means of said third switch,said means for periodically engaging said contacts of said fourthswitch,

said means for periodically disengaging said contacts of said fifthswitch and said means for periodically engaging said contacts of saidseventh switch with said second motor; and

of Said bridges to said responsive means;

means coupled to said sequentially coupling means and said responsivemeans for advancing said coupling means to the next bridge circuit uponthe balancing wiper arm of the respective adjustable potentiometer; y

means responsive to the output of said bridge circuits for producing anoutput signal upon a balance thereclock means drivingly connected -tosaid sequentially of;

engaging means of said first and second switches for a second motor; lsequentially engaging the contacts thereof. means coupled to saidresponsive means for energizing 8. A system for controlling a pluralityof sprinkler stasaid motor upon an output signal from said respontionscomprising: sive means;

a power supply; means coupled to said responsive means and said bridge amotor; circuits for sequentially coupling the outputs of said meansconnecting said power supply with said motor bridges to said responsivemeans;

to energize said motor, said connecting means includmeans drivinglyconnecting said second motor to said ing first switch means forpermitting current fiow sequentially coupling means for advancing saidsethrough said connecting means at selected hours of 15 quentiallycoupling means to the next bridge circuit the day and second switchmeans for permitting curupon energization of said motor; y rent fiowthrough said connecting means Von selected a first switch having aplurality of contacts and means days of the week; for sequentiallyengaging said contacts; a master potentiometer connected to said powersupply; means coupling each of said contacts of said first switch meansdrivingly connecting the wiper arm of said master to one of saidsprinkler stations of said first group; potentiometer to said motor; asecond switch having a plurality of contacts and a plurality ofadjustable potentiometers, each of said means for sequentially engagingsaid contacts;

potentiometers corresponding to at least one of said means coupling eachof said contacts of said second sprinkler stations, said adjustablepotentiometers switch to one of said sprinkler stations of' said secondbeing connected to said power supply to form a plugroup; rality ofbridge circuits with said master potentioma third switch having a pairof contacts and an arm eter, the output of each bridge circuit appearingbel movable into engagement with either of said contween the Wiper armof the master pOentiOmCer and tacts, one of said contacts beingelectrically conthe wiper arm of the respective adjustable potentinestedto said sequentially engaging means of said ometer; first switch and theother of said contacts being elecmerls rtSPC'rlSVe t0 the Output 0f Saidbridge Circuits trically connected to the sequentially engaging meansfor producing an output signal upon a balance of said second switch;thereof; means electrically connecting said movable arm to said meanscoupled to said responsive means and to said power supply; and

bridge circuits for sequentially coupling the outputs lmeans drivinglyconnected to said second motor and to said movable arm for alternatelyengaging said movable arm with said one contact and said other contact.

10. The system of claim 9 wherein said alternately enof the precedingbridge circuit; 40 first means for coupling each of a first portion ofsaid sprinkler stations to said power supply whenever said sequentiallycoupling means is coupling the output of gaging means comprises a diskwith a portion having a lesser radius than the remainder ofthe disk.

11. A system for controlling a plurality of sprinkler stations dividedinto first and second groups comprising:

its respective bridge circuit to said responsive means;

second means for coupling each of 4a second portion of said sprinklerstations to said power supply whenever said sequentially coupling meansis coupling the output of its respective bridge circuit to saidresponsive means; and

means coupled to said advancing means for actuating said second meansafter each of said first portion of stations has had the output of itsrespective bridge circuit coupled to said responsive means.

9. A system for controlling a plurality of sprinkler a power supply;

a first switch having a plurality of contacts and means for sequentiallyengaging said contacts;

means for connecting said sequentially engaging means to said powersupply;

v a first plurality of switches each having a pair of relatively movablecontacts, a first contact of eachy of said swit-ches being connected tooneof said contacts of said first switch;

a second plurality of switches each having a pair of relatively movablecontacts;

stations divided into first and second groups comprising: meansconnecting each of said second contacts of said a power supply; rstplurality of switches with each of the first cona motor; tacts of saidsecond plurality of switches; means connecting said power supply withsaid motor a second switch having a plurality of contacts and toenergize said motor, said connecting means inmans for sequentially@Ugagrlg Sad CODtCtS cluding first switch means for permitting currentfiow the Scond Coma 0f each 0f Sad second Plurahty 0f through saidconnecting means at selected hours of Svfltches belnconnected to one ofthe contacts of the day and second switch means for permitting cur- SadScond SV/Itch; rent fiow through said connecting means on selected amotor mdudlflg an .eXC1t1n.g. Wmding means connecting said excitingwinding to said sequedays of the Week tially engaging means of saidsecond switch; a master Pmlometer C.Onnected.to Said power supply amaster potentiometer connected to said power supply; means drivinglyconnecting the wiper arm of said masmeans dvingly connecting the Wiperarm of Said mas ter potentiometer to said motor; ter potentiometer toSaid motor; a plurality of adjustable potentiometers each of Said aplurality of adjustable potentiometers, each of said potentiometersCOrreSPOldtrlg t0 at least 011 0f Said 70 potentiometers correspondingtoat least one of said Sprinkler SttiOrlS, Saidadjustable.potentiometers besprinkler stations, said adjustablepotentiometers being connected to said power supply to form a pluraliingconnected to said power supply to form a pluty of bridge circuits withsaid master potentiometer, rality of bridge circuits with said masterpotentiomthe output of each bridge cir-cuit appearing between eter, theoutput of each of said bridge circuits apthe wiper arm of the masterpotentiometer and the pearing between the Wiper arm of the master poy15tentiometer and the wiper arm of the respective adjustablepotentiometer;

a third switch having a plurality of contacts and means for sequentiallyengaging said contacts, each of said contacts being connected to thewiper arm of one of said adjustable potentiometers;

a transistor amplier having an input and an output,

said input being connected to said sequentially engaging means of saidthird switch;

a relay having a coil and a pair of contacts engageable by energizatioriof said coil, said coil being connected to said output of said amplifierwhereby it is energized upon conduction by said amplier;

a second motor including an exciting winding;

means electrically connecting said exciting winding with one of saidcontacts of said relay;

means connecting said other contact of said relay to said sequentiallyengaging means of said second switch;

means drivingly connecting said sequentially engaging means of saidthird switch to said second motor;

a fourth switch having a plurality of contacts and means forsequentially engaging said contacts;

means coupling each of said contacts of said fourth switch to one ofsaid sprinkler stations of said first group;

a fifth switch having a plurality of contacts and means for sequentiallyengaging said contacts;

means coupling each of said contacts of said fth switch to one of saidsprinkler stations of said second group;

a sixth switch having a pair of contacts and an arm movable intoengagement with either of said contacts, one of said contacts beingelectrically connected to said sequentially engaging means of saidfourth switch and the other of said contacts being electricallyconnected to the sequentially engaging means ot said fth switch',

means electrically connecting said movable arm to said power supply,said means including a seventh switch;

means drivingly connected to said second motor and to said movable armfor alternately engaging said movable arm with said one contact and saidother Contact', and

means drivingly connected to said second motor for closing said seventhswitch when the sequentially engaging means of either said fourth switchor said fth switch is in engagement with one of the contacts thereof.

i2. The system of claim 11 wherein said alternately engaging meanscomprises a disk with a portion having a lesser radius than theremainder of the disk.

References Cited by the Examiner UNITED STATES PATENTS 3,200,303 7/1965Maxwell 307-141 X ORIS L. RADER, Primary Examiner. 30

T. I. MADDEN, Assistant Examiner.

1. A SYSTEM FOR CONTROLLING A PLURALITY OF SPRINKLER STATIONSCOMPRISING: A POWER SUPPLY; A MOTOR; MEANS CONNECTING SAID POWER SUPPLYWITH SAID MOTOR TO ENERGIZE SAID MOTOR, SAID CONNECTING MEANS INCLUDINGFIRST SWITCH MEANS FOR PERMITTING CURRENT FLOW THROUGH SAID CONNECTINGMEANS AT SELECTED HOURS OF THE DAY AND SECOND SWITCH MEANS FORPERMITTING CURRENT FLOW THROUGH SAID CONNECTING MEANS ON SELECTED DAYSOF THE WEEK; A MASTER POTENTIOMETER CONNECTED TO SAID POWER SUPPLY;MEANS DRIVINGLY CONNECTING THE WIPER ARM OF SAID MASTER POTENTIOMETER TOSAID MOTOR; A PLURALITY OF ADJUSTABLE POTENTIOMETERS, EACH OF SAIDPOTENTIOMETERS CORRESPONDING TO ONE OF SAID SPRINKLER STATIONS, SAIDADJUSTABLE POTENTIOMETERS BEING CONNECTED TO SAID POWER SUPPLY TO FORM APLURALITY OF BRIDGE CIRCUITS WITH SAID MASTER POTENTIOMETER, THE OUTPUTOF EACH BRIDGE CIRCUIT APPEARING BETWEEN THE WIPER ARM OF THE MASTERPOTENTIOMETER AND THE WIPER ARM OF THE RESPECTIVE ADJUSTABLEPOTENTIOMETER; A SWITCH HAVING A PLURALITY OF CONTACTS AND MEANS FORSEQUENTIALLY ENGAGING SAID CONTACTS, EACH OF SAID CONTACTS BEINGCONNECTED TO THE WIPER ARM OF ONE OF SAID ADJUSTABLE POTENTIOMETERS; ATRANSISTOR AMPLIFIER HAVING AN INPUT AND AN OUTPUT, SAID INPUT BEINGCONNECTED TO SAID SEQUENTIALLY ENGAGING MEANS OF SAID SWITCH; A RELAYHAVING A COIL AND A PAIR OF CONTACTS ENGAGEABLE BY ENERGIZATION OF SAIDCOIL, SAID COIL BEING CONNECTED IN SERIES WITH SAID OUTPUT OF SAIDAMPLIFIER WHEREBY IT IS ENERGIZED UPON CONDUCTION OF SAID AMPLIFIER; ASECOND MOTOR; MEANS DRIVINGLY CONNECTING SAID SECOND MOTOR WITH SAIDSEQUENTIALLY ENGAGING MEANS OF SAID SWITCH; AND MEANS FOR CONNECTINGSAID MOTOR TO SAID POWER SUPPLY, SAID MEANS INCLUDING SAID CONTACTS OFSAID RELAY.